Problem: Umaima eats at a cafe and the cost of her meal is $\$42.00$. She would like to leave a $10\%$ tip. What is her total bill including tip?
Explanation: The tip amount is equal to $10\% \times \$42.00$ To calculate a $10\%$ tip, move the decimal point in $\$42.00$ one place to the left. $10\%$ $\times \$42.00$ $\$4.20$ The cost of the meal plus the amount of the tip will equal the total bill amount. $\$42.00 + \$4.20 = $ $\$46.20$ The total cost of the bill is $\$46.20$.